Expectation of primordial gravity waves generated during inflation

TL;DR

This paper investigates how incorporating an objective collapse model into inflationary cosmology alters primordial gravitational wave predictions, notably suppressing the B-mode spectrum while preserving temperature anisotropy predictions.

Contribution

It introduces a realistic collapse mechanism into inflationary models, providing a new explanation for the suppressed B-mode polarization observed in the CMB.

Findings

B-mode spectrum is strongly suppressed with collapse models.

Temperature anisotropy predictions remain unchanged.

Collapse models align predictions with observations.

Abstract

The inflationary paradigm is extremely successful regarding predictions of temperature anisotropies in the CMB. However, inflation also makes predictions for a CMB B-mode polarization, which has not been detected. Moreover, the standard inflationary paradigm is unable to accommodate the evolution from the initial state, which is assumed to be symmetric, into a non-symmetric aftermath. In Phys. Rev. D 96, 101301(R), we show that the incorporation of an element capable of explaining such a transition drastically changes the prediction for the shape and size of the B-mode spectrum. In particular, employing a realistic objective collapse model in a well-defined semiclassical context, we find that, while predictions of temperature anisotropies are nor altered (with respect to standard predictions), the B-mode spectrum gets strongly suppressed--in accordance with observations. Here we present an in-depth discussion of that analysis, together with the details of the calculation.